When the climate warmed abruptly after the last ice age almost 12,000 years ago, it greatly expanded areas of low oxygen in the ocean.

Sarah Moffitt of Bodega Marine Lab at the University of California at Davis studied a sediment core drilled from the ocean floor that provided a record of this abrupt climate shift.

MOFFITT: “What we found is that sea floor communities are really, dramatically disturbed by abrupt oxygen loss and abrupt climate warming.”

It’s an effect that scientists fear is happening again. Only marine creatures with extra-large gills and other special adaptations can survive in low oxygen zones, so current climate trends may put many ocean species at risk.

Moffitt’s research also shows that while the damage from low oxygen zones can happen over the course of a century, the recovery can take up to a thousand years. Moffitt says scientists are already seeing signs that low oxygen zones are expanding again.

MOFFITT: “When low oxygen zones expand, that expansion is really removing habitat from organisms that we care about, that we harvest, and so it has consequences for coastal fishing and fishing economies.”